Kaijuu no Kodomo

Ruka Azumi's ordinary summer vacation revolves around spending all her time on the handball court to avoid her only housemate, her alcoholic mother. When an incident at practice leads to Ruka's exclusion from the handball team, she is forced to find other outlets to enjoy herself, eventually winding up at the aquarium where her father works. There, she meets Umi, a mysterious boy raised by dugongs…